RF-ID systems in the past, which may use battery-less or passive transponders, which depend upon the rectification of the interrogation signal for power, have mainly been comprised of transponders with read-only capability. The transponders were constrained in size, to facilitate implantation, for example, in animals, and in cost to keep manufacture expenses at a minimum. However, the applications for RF-ID systems continued to grow and with it, technical demands for a better, more improved RF-ID system.
One major improvement to the existing RF-ID systems, was the implementation of a Read-Write transponder. With Read/Write capability, numerous applications arose such as airline baggage tracking, warehouse goods tracking, and assembly line piece part tracking. One growing area of interest in Read/Write applications is in security access and toll applications which require remote Read and Programing(Write) functionality. Remote Read and Programing transponders are, however, prone to being tampered with due to the potential gain of succeeding, i.e. unauthorized access to a secure area or free passage through a toll booth. Data security and protection against data manipulation are essential in these applications.